Binding Memory and Relational Mechanisms: The Central Role of Binding in Fluid Intelligence

Fluid intelligence (Gf) and working memory (WM) are strongly correlated, with the binding hypothesis suggesting that this relationship is driven by the capacity to bind content to context. However, it remains unclear how various binding functions overlap and relate to Gf. This study investigates the extent of overlap between five binding functions (item-to-location binding, item-to-item binding, relational integration, relation processing, and perceptual feature binding) and their relationship with Gf. A sample of 174 young adults completed three visuospatial variants of tasks measuring these five binding functions alongside three Gf tasks. Data were analyzed using structural equation modeling and latent network analysis to evaluate shared and unique variances. Results indicated significant overlap among the binding functions, with item-to-location and item-to-item binding best modeled as a single latent variable termed binding memory. The shared variance among binding memory and the remaining binding functions was represented by a higher-order, process-general latent factor labeled Binding which was found to be statistically isomorphic with Gf. Latent network analysis further revealed that binding memory, relational integration, and relation processing each exhibited unique, direct relationships with Gf, whereas perceptual feature binding related to Gf only indirectly. These findings indicate that an overarching, domain-general ability to form and utilize bindings in a goal-directed manner is deeply intertwined with Gf, supporting theories emphasizing binding and relational mechanisms in Gf.